Botnet takedowns 'don't hurt crooks enough'

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The takedowns of the Mariposa and Waladec botnets last week were victories for the good guys, but security experts warn that although cybercrooks suffered a bloody nose they collectively retain the upper hand in their ongoing conflict with law enforcement and its security industry allies.

"We have had significant victories against several botnets in the past but that hasn't stopped the growth in malware or the growth in spam or in information theft," said Rik Ferguson, a security consultant at Trend Micro. "So, while we continue to win significant battles, winning the war will need closer cooperation between governments [and] law enforcement agencies on an ongoing basis rather than on an operational basis."

Ferguson thinks that white hats remain outgunned by cybercrooks. He called for harmonisation of e-crime laws, to get rid of safe havens, and closer international cooperation in fighting internet crime. He added that ISPs have a vital role to play in curbing the botnet scourge. He continued:

I'm not convinced we're winning this - it still needs organisations like ISPs to be willing to identify affected machines and quarantine them while informing customers of this. There is also a need for the harmonisation of laws. there are some countries where it isn't illegal to engage in online criminal activities - or countries where laws are outdated or different to other countries, so there is no harmonisation. Once harmonised, it'll be easier to prosecute and apply common laws across geographical boundaries.

Intelligence sharing between national governments on matters of cybercrime will also be key. There is already intelligence sharing for other types of crimes, why not for cybercrime?

Gunter Ollmann, vice president of Research at security firm Damballa, said that going after the crooks in controls of running botnets rather than the domains they used was the only truly effective strategy. Even then difficulties abound.

I've found the takedown of the domain names used by the botnet operators to be ineffective. The bad guys simply register new ones and carry on with their business. For example, one botnet that we track has used over 80,000 different command and control domain names since we've been monitoring them over four years. At any point in time they have around 5,000 live and in use. No sooner is one domain name closed, sinkholed, or hijacked, than they simply register some more and continue business.

Ollman, a computer scientist and security expert of many years standing, has published a number of research papers over recent months about botnets in corporate environments. His research suggests that even if one cybercrime ring is brought down other crooks will step in to exploit gaps in the market. Nonetheless pursuing the bad guys is a worthwhile endeavour.

This process is complicated by the fact that ownership of compromised systems often changes hands very quickly in the digital underground, he explained:

It is important to focus on the criminal operators themselves - it's the only way to shut down the botnet. However, it doesn't pay to delay in taking down the operators. Given the trend in buying/selling/renting and horse-trading (eg trading botnet victims in one country with a botnet operator that has botnet victims in another) access to the victim hosts can change hands rapidly. As part of the handover of victims or sections of the botnet, the new operator installs their own (new) botnet agent.

Building and running botnets is a highly competitive business. If one operator goes down, it creates new opportunities for the other botnet operators. It's not as if the victims have suddenly become secure in the interim.